US20030112488A1 - Integrated optical unit for use with miniature optical discs - Google Patents
Integrated optical unit for use with miniature optical discs Download PDFInfo
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- US20030112488A1 US20030112488A1 US10/025,601 US2560101A US2003112488A1 US 20030112488 A1 US20030112488 A1 US 20030112488A1 US 2560101 A US2560101 A US 2560101A US 2003112488 A1 US2003112488 A1 US 2003112488A1
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- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 claims abstract description 15
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- 229910052782 aluminium Inorganic materials 0.000 claims description 5
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- 230000013011 mating Effects 0.000 description 2
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Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1372—Lenses
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
- G02B6/4214—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/43—Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/123—Integrated head arrangements, e.g. with source and detectors mounted on the same substrate
Definitions
- the present invention generally relates to optical elements for use in transmitting laser light to and from an optical disc, and more particularly to techniques for miniaturizing such optical elements.
- a principle object of the present invention is an improvement in the manufacture of glass components and related structures used in optical disc systems.
- the present invention has advantageous application with miniature optical discs.
- FIG. 1 is a plan view of a glass wafer that has been etched to provide multiple lens elements
- FIG. 2 is a plan view of a glass wafer that has been etched to provide multiple base elements
- FIG. 3 is a perspective view of a lens element after it has been separated from the wafer of FIG. 1, the view looking at the back side of the lens element;
- FIG. 4 is a side view of an assembled optical unit and supporting semiconductor chip that provides an electro-optical interface, the optical unit including a lens element mounted on a base element.
- a clear glass wafer 10 is shown with multiple lens elements 12 therein, the lens elements having been defined by etching away portions of the wafer.
- the lens elements 12 Before the lens elements 12 are etched to arrive at the configuration shown in FIG. 1, certain surface features are formed, as described below in connection with FIG. 3.
- each element 12 has a slot 14 that preferably extends halfway down through the element to enable formation of a reflective surface therein.
- the elements 12 are supported as part of the etched wafer 10 by vertical glass rods 16 that remain after portions of the wafer have been etched out.
- Starting wafers 10 can be cut from larger sheets of optical-grade glass in circular diameters that correspond to the size of conventional silicon wafers used in semiconductor manufacturing. Such wafers are typically sized in two-inch increments, such as six-inch, eight-inch, or ten-inch wafers.
- a V-groove 18 can be cut at one point in the circumference of the wafer 10 for automatic alignment purposes with handling equipment.
- a flat edge extending several centimeters along one edge can be used instead of the V-groove 18 specifically shown.
- Such flat edges are typically used with six-inch silicon wafers.
- a preferred thickness for a six-inch glass wafer that is suitable for the present invention is about 0.75 mm.
- the etching used to produce the structure shown in FIG. 1 can be accomplished using techniques that are well known in the semiconductor industry.
- a conventional photoresist is applied to the starting wafer.
- an image of the pattern of material to be etched out is exposed on the photoresist using conventional semiconductor photolithography.
- the exposed photoresist is then dissolved and removed from the wafer.
- the wafer is subjected to a plasma etching technique that cuts straight through the glass wafer in the areas that are not covered by the photoresist.
- plasma etching techniques are conventional and are used for etching silicon dioxide and other glass-like materials in semiconductor processing.
- the remaining photoresist is then removed from the wafer.
- FIG. 2 a glass wafer 20 is shown after it has been etched using a different pattern to produce multiple base elements 22 , which are interconnected with each other and the wafer 20 by glass rods 24 in a manner similar to that previously described in connection with the wafer 10 of FIG. 1.
- the lens elements 12 and base elements 22 are separated from the wafers by cutting through the rods 16 and 24 .
- the cutting operation can be performed using a conventional diamond saw process.
- FIG. 3 shows additional details of one of the lens elements 12 that has been separated from its starting wafer.
- the slot 14 can be seen extending from a front surface 26 to a depth of almost exactly one-half the thickness of the element 12 .
- a reflective film is formed on the walls within the slot 14 to provide a mirror 28 .
- a front lens 30 is formed at one end of the element 12 extending inward from the front surface 26 .
- a back lens 32 is juxtaposed next to the front lens 30 and extends inward from a back surface 34 of the lens element 12 , each lens occupying almost exactly one-half the thickness of the element 12 .
- each of the lenses 30 and 32 has a curved surface that retains the same curvature in cross-sectional planes parallel to the opposed front and back planar surfaces 26 and 34 . This is caused by plasma etching straight down into the wafer.
- the two lenses 30 and 32 permit laser light to enter and exit the lens element 12 along different parallel paths, as explained below.
- Partially reflective mirrors 36 and 38 at opposite ends of the element 12 are used to reflect light beams traveling through the lens element.
- the reflective thin films preferably include a transition metal with a high reflection value in a form that is suitable for conventional deposition techniques. Certain oxides, nitrides, sulfides, and fluorides of such metals are stable, highly reflective and suitable for deposition on glass surfaces. Of these materials, our experiments show that titanium nitride meets these criteria and can be deposited in different thicknesses to achieve partial reflectivity of a desired value.
- Mirrors 36 and 38 are constructed to be about 62 percent reflective. This is preferably accomplished during processing by depositing a thin titanium nitride film on the angled surfaces at the opposite ends of the lens element 12 and on the walls within the slot 14 . The thickness of the titanium nitride film is controlled to achieve the preferred 62 percent reflectivity.
- Mirror 28 can be made with a like thickness of titanium nitride, or can be provided with a much thicker titanium deposition to make it much more reflective, preferably at least 90 percent reflective.
- the mirrors 28 , 36 , and 38 preferably comprise multiple film layers including a protective outer coating.
- FIG. 4 an exploded view of an assembled optical unit 40 is shown supported by a semiconductor chip 42 , which functions as an electro-optical interface for the optical unit 40 .
- the optical unit 40 and chip 42 together define an electro-optical device for reading an optical disc (not shown).
- the optical unit 40 includes a lens element 12 mounted on a base element 22 in the manner indicated.
- extensions 44 and 46 of the rods 16 of lens element 12 fit into corresponding recesses 48 and 50 in the top surface 52 of the base element 22 .
- Extensions 54 and 56 of the rods 24 of the base element 22 rest against the bottom surface 58 of the lens element 12 .
- FIG. 2 shows the base elements 22 without recesses for use in such an alternative assembly technique.
- Photodetectors 60 and 62 are provided at the upper surface 64 of the semiconductor chip 42 .
- the photodetectors 60 and 62 aligned with respective light beams 66 and 68 that originate from a light beam 70 returning from an optical disc (not shown) entering the lens element 12 through the back lens 32 .
- the split-beam approach using a pair of photodetectors 60 and 62 as depicted in FIG. 4 compares corresponding electrical signals within the chip 42 to eliminate unwanted signal noise.
- Band-pass filters can also be added on surface portions 72 and 74 of the upper surface 52 of the base element 22 in the path of light beams 66 and 68 to filter out unwanted noise.
- the entire base element 22 can be clad with a thin film that filters out unwanted light noise.
- a laser diode 76 that emits a laser light beam 78 , which is reflected upward by a mirror 80 on a 45° angled surface of the base element 22 .
- Mirror 80 is constructed to be nearly 100 percent reflective.
- the laser diode 76 is supported by a mounting block 82 that enables precise alignment of the light beam 78 with the mirror 80 .
- the light beam 78 after reflection by the mirror 80 , passes through the base element 22 and enters the lens element 12 just beneath the slot 14 .
- the light beam 78 is substantially reflected by the mirror 28 in the slot 14 back to the right in the view of FIG. 4 horizontally at the mirror 36 .
- Mirror 28 is oriented at a 45° angle to reflect the upwardly directed beam horizontally (or longitudinally with respect to the lens element 12 ) at the mirror 36 .
- the mirror 36 is constructed to be about 62 percent reflective, about 62 percent of the light beam 78 is reflected up and passes out through the lens 32 as focused laser light beam 82 .
- Mirror 36 may be oriented at 45° to the longitudinal direction of the lens element 12 or may have a slightly different angle to accommodate the orientation of the lenses 30 and 32 .
- the light beam 82 is directed at an optical disc (not shown), which partially reflects back the information-containing beam 70 .
- the entering beam 70 returns on a path that is spaced from and generally parallel to the out-going beam 82 , as directed by optics (not shown) between the lens element 12 and the optical disc that is being read by the system.
- the information-containing light beam 70 enters the lens element 12 through the back lens 32 , which directs the beam downward at the mirror 36 .
- the light beam 70 is split by the mirror 36 into horizontal and downward components, the downward component corresponding to the beam 68 that impinges on photodetector 62 , as previously discussed.
- the horizontal component 84 of the beam 70 that is reflected by the mirror 36 passes through the back half of the lens element 12 , thus avoiding the mirror 28 in the slot 14 , and continues on horizontally striking the mirror 38 .
- the mirror 38 which is oriented at 45° to the horizontal direction, reflects most of the horizontal component 84 of the information-containing beam 70 downward as beam 66 , which impinges on the photodetector 60 .
- the photodetector 60 is in electrical communication with analog-to-digital (A/D) converter circuitry 86 within the semiconductor chip 42 .
- the photodetector 62 is in electrical communication with A/D converter circuitry 88 within the chip 42 .
- the A/D converters 86 and 88 are connected to logic circuitry within the chip 42 that performs data and control functions and communicates with other system components (not shown).
- the lens element 12 and base element 22 are cut from separate wafers 10 and 20 , shown in FIGS. 1 and 2. This is useful to permit different processes to be performed on the separate parts.
- the mirror 80 maybe formed in a different way from mirrors 28 , 36 and 38 . Since mirror 36 needs to be partially reflective to split the returning beam 70 into two components, the mirrors 28 and 38 can be made partially reflective for simplification of the process. However, it will be appreciated that mirrors 28 and 80 can be made fully reflective or almost fully reflective, consistent with process design. If the base element 22 is processed separately from the lens element 12 , it is convenient to use a different material to make mirror 80 fully reflective. However, if a more complex process is used to permit forming both partially reflective mirror surfaces and fully reflective mirror surfaces during the process sequence, then the lens element 12 and base element 22 can be cut from a single glass wafer.
- mirrors 36 and 38 are each made to be about 62 percent reflective, then about 38 percent of the returning beam 70 will fall on each of the photodetectors 60 and 62 .
- the mirror 28 can be made in a similar way to mirrors 36 and 38 to be partially reflective, or can be made to be essentially fully reflective. It will also be appreciated that if mirror 38 is made to be almost fully reflective, mirror 36 can be made to be about 50 percent reflective to have the same light intensity impinging on the photodetectors 60 and 62 . However, this will reduce the intensity of the out-going laser light beam 82 .
- multiple lens elements 12 are made from a glass wafer, such as the wafer 10 , as follows.
- a first photoresist pattern is formed with openings that define the slots 14 for each of the lens elements 12 .
- a conventional fluoride-based plasma etch step is performed for a time duration that etches openings corresponding to the slots 14 to a depth almost exactly halfway through the wafer 10 .
- a conformal titanium nitride deposition step is performed to coat the walls within the openings with a thin film of titanium nitride, one surface of which later defines mirror 28 .
- the thickness of the titanium nitride deposition is preferably controlled to make the mirror 28 more than 90 percent reflective.
- the photoresist is then stripped and a second photoresist pattern is formed that has openings that define the angled surfaces at the opposite ends of each lens element 12 where the mirrors 36 and 38 are to be formed.
- a second plasma etch is performed to cut a second set of openings vertically down into the wafer 10 , the openings having walls that include the surfaces on which the mirrors 36 and 38 will be formed.
- a second conformal titanium nitride deposition step is performed to coat the walls with the second set of openings with titanium nitride, the walls including surfaces that define the position of the mirrors 36 and 38 on the finished lens elements 12 .
- the second photoresist pattern is then stripped off the wafer 10 .
- the thickness of the second titanium nitride deposition is preferably controlled so that the mirrors 36 and 38 are very nearly 62 percent reflective.
- the process continues with formation of a third photoresist pattern on the wafer 10 with openings for defining the front lens 30 of each element 12 .
- a plasma etch cuts down into the wafer 10 from the front surface 26 to a depth that is almost precisely halfway through the thickness of the wafer, which is achieved by controlling the etch duration.
- the front lens 30 of each element 12 will be provided by this patterning and etching sequence.
- the wafer 10 is turned upside down and a fourth photoresist pattern is formed on the back side of the wafer 10 to define the surfaces that will become the back lens 32 of each lens element 12 .
- a plasma etch is performed to etch openings in the wafer 10 through corresponding openings in the photoresist pattern to define surfaces that include the surfaces of each back lens 32 of each lens element 12 .
- the fourth photoresist pattern is then stripped away. As seen in FIG. 3, the result of the etching is that back lens 32 is defined by a surface cut straight down from the back surface 34 halfway through the lens element 12 .
- a fifth photoresist pattern is formed to define the outlines of the lens elements 12 , as shown in FIG. 1, with their connecting rods 16 .
- This photoresist pattern can be formed on the front side of the wafer 10 , or a mirror-image pattern can be formed on the back side.
- a plasma etch then is performed to cut through the wafer 10 to provide the structures shown in FIG. 1. Individual lens elements 12 are then provided by cutting the rods 16 as previously described.
- a similar but less complicated sequence of steps can be used to form the base elements 22 within the wafer 20 of FIG. 2. Since it is desirable for mirror 80 to be fully or almost fully reflective, a relatively thick titanium nitride deposition can be used. Alternatively, an aluminum deposition can be performed. In either case, the deposition step proceeds after appropriate windows are etched through a photoresist pattern. If aluminum is used for the mirrors 80 of each base element 22 , a nearly 100 percent reflective surface can be achieved. To keep the mirrors 80 from oxidizing and adversely affecting their reflectivity, a thin glass layer is deposited on the aluminum immediately after the metal deposition step.
Abstract
Description
- The present invention generally relates to optical elements for use in transmitting laser light to and from an optical disc, and more particularly to techniques for miniaturizing such optical elements.
- A principle object of the present invention is an improvement in the manufacture of glass components and related structures used in optical disc systems. The present invention has advantageous application with miniature optical discs.
- Other objects and advantages of the invention will become apparent from the following description of the invention, with reference to the accompanying drawings, in which:
- FIG. 1 is a plan view of a glass wafer that has been etched to provide multiple lens elements;
- FIG. 2 is a plan view of a glass wafer that has been etched to provide multiple base elements;
- FIG. 3 is a perspective view of a lens element after it has been separated from the wafer of FIG. 1, the view looking at the back side of the lens element; and
- FIG. 4 is a side view of an assembled optical unit and supporting semiconductor chip that provides an electro-optical interface, the optical unit including a lens element mounted on a base element.
- Referring specifically to FIG. 1, a
clear glass wafer 10 is shown withmultiple lens elements 12 therein, the lens elements having been defined by etching away portions of the wafer. Before thelens elements 12 are etched to arrive at the configuration shown in FIG. 1, certain surface features are formed, as described below in connection with FIG. 3. In particular, eachelement 12 has aslot 14 that preferably extends halfway down through the element to enable formation of a reflective surface therein. Theelements 12 are supported as part of theetched wafer 10 byvertical glass rods 16 that remain after portions of the wafer have been etched out. - Starting
wafers 10 can be cut from larger sheets of optical-grade glass in circular diameters that correspond to the size of conventional silicon wafers used in semiconductor manufacturing. Such wafers are typically sized in two-inch increments, such as six-inch, eight-inch, or ten-inch wafers. A V-groove 18 can be cut at one point in the circumference of thewafer 10 for automatic alignment purposes with handling equipment. Alternatively, as with some conventional silicon wafers, a flat edge extending several centimeters along one edge can be used instead of the V-groove 18 specifically shown. Such flat edges are typically used with six-inch silicon wafers. A preferred thickness for a six-inch glass wafer that is suitable for the present invention is about 0.75 mm. - The etching used to produce the structure shown in FIG. 1 can be accomplished using techniques that are well known in the semiconductor industry. A conventional photoresist is applied to the starting wafer. Then, an image of the pattern of material to be etched out is exposed on the photoresist using conventional semiconductor photolithography. The exposed photoresist is then dissolved and removed from the wafer. Next, the wafer is subjected to a plasma etching technique that cuts straight through the glass wafer in the areas that are not covered by the photoresist. Such plasma etching techniques are conventional and are used for etching silicon dioxide and other glass-like materials in semiconductor processing. The remaining photoresist is then removed from the wafer.
- Now referring to FIG. 2, a
glass wafer 20 is shown after it has been etched using a different pattern to producemultiple base elements 22, which are interconnected with each other and thewafer 20 byglass rods 24 in a manner similar to that previously described in connection with thewafer 10 of FIG. 1. After formation of thewafers lens elements 12 andbase elements 22 are separated from the wafers by cutting through therods - FIG. 3 shows additional details of one of the
lens elements 12 that has been separated from its starting wafer. Theslot 14 can be seen extending from afront surface 26 to a depth of almost exactly one-half the thickness of theelement 12. A reflective film is formed on the walls within theslot 14 to provide amirror 28. Afront lens 30 is formed at one end of theelement 12 extending inward from thefront surface 26. A back lens 32 is juxtaposed next to thefront lens 30 and extends inward from aback surface 34 of thelens element 12, each lens occupying almost exactly one-half the thickness of theelement 12. It will be noted that each of thelenses 30 and 32 has a curved surface that retains the same curvature in cross-sectional planes parallel to the opposed front and backplanar surfaces lenses 30 and 32 permit laser light to enter and exit thelens element 12 along different parallel paths, as explained below. Partiallyreflective mirrors element 12 are used to reflect light beams traveling through the lens element. - Various reflective thin films formed on the glass surface of the
elements -
Mirrors lens element 12 and on the walls within theslot 14. The thickness of the titanium nitride film is controlled to achieve the preferred 62 percent reflectivity.Mirror 28 can be made with a like thickness of titanium nitride, or can be provided with a much thicker titanium deposition to make it much more reflective, preferably at least 90 percent reflective. Themirrors - Referring to FIG. 4, an exploded view of an assembled
optical unit 40 is shown supported by asemiconductor chip 42, which functions as an electro-optical interface for theoptical unit 40. Theoptical unit 40 andchip 42 together define an electro-optical device for reading an optical disc (not shown). Theoptical unit 40 includes alens element 12 mounted on abase element 22 in the manner indicated. In particular,extensions rods 16 oflens element 12 fit into corresponding recesses 48 and 50 in thetop surface 52 of thebase element 22.Extensions rods 24 of thebase element 22 rest against thebottom surface 58 of thelens element 12. The mating of therod extensions lens element 12 with thebase element 22. Similar recesses can be provided in the top surface of thesemiconductor chip 42 for receiving the ends of therods 24 on the bottom of thebase element 22. Such recesses are preferred but are optional. External fixtures can be used as an alternative assembly technique and adhesive applied to the mating surfaces. FIG. 2 shows thebase elements 22 without recesses for use in such an alternative assembly technique. -
Photodetectors upper surface 64 of thesemiconductor chip 42. Thephotodetectors respective light beams light beam 70 returning from an optical disc (not shown) entering thelens element 12 through the back lens 32. The split-beam approach using a pair ofphotodetectors chip 42 to eliminate unwanted signal noise. Band-pass filters (not shown) can also be added onsurface portions upper surface 52 of thebase element 22 in the path oflight beams entire base element 22 can be clad with a thin film that filters out unwanted light noise. - Mounted above the
semiconductor chip 42 is alaser diode 76 that emits alaser light beam 78, which is reflected upward by amirror 80 on a 45° angled surface of thebase element 22. Mirror 80 is constructed to be nearly 100 percent reflective. Thelaser diode 76 is supported by amounting block 82 that enables precise alignment of thelight beam 78 with themirror 80. Thelight beam 78, after reflection by themirror 80, passes through thebase element 22 and enters thelens element 12 just beneath theslot 14. Thelight beam 78 is substantially reflected by themirror 28 in theslot 14 back to the right in the view of FIG. 4 horizontally at themirror 36.Mirror 28 is oriented at a 45° angle to reflect the upwardly directed beam horizontally (or longitudinally with respect to the lens element 12) at themirror 36. - Because the
mirror 36 is constructed to be about 62 percent reflective, about 62 percent of thelight beam 78 is reflected up and passes out through the lens 32 as focusedlaser light beam 82.Mirror 36 may be oriented at 45° to the longitudinal direction of thelens element 12 or may have a slightly different angle to accommodate the orientation of thelenses 30 and 32. Thelight beam 82 is directed at an optical disc (not shown), which partially reflects back the information-containingbeam 70. The enteringbeam 70 returns on a path that is spaced from and generally parallel to the out-goingbeam 82, as directed by optics (not shown) between thelens element 12 and the optical disc that is being read by the system. - Referring to FIGS. 3 and 4 together, the information-containing
light beam 70 enters thelens element 12 through the back lens 32, which directs the beam downward at themirror 36. Thelight beam 70 is split by themirror 36 into horizontal and downward components, the downward component corresponding to thebeam 68 that impinges onphotodetector 62, as previously discussed. Thehorizontal component 84 of thebeam 70 that is reflected by themirror 36 passes through the back half of thelens element 12, thus avoiding themirror 28 in theslot 14, and continues on horizontally striking themirror 38. Themirror 38, which is oriented at 45° to the horizontal direction, reflects most of thehorizontal component 84 of the information-containingbeam 70 downward asbeam 66, which impinges on thephotodetector 60. Thephotodetector 60 is in electrical communication with analog-to-digital (A/D)converter circuitry 86 within thesemiconductor chip 42. Likewise, thephotodetector 62 is in electrical communication with A/D converter circuitry 88 within thechip 42. The A/D converters chip 42 that performs data and control functions and communicates with other system components (not shown). - In the previous description, the
lens element 12 andbase element 22 are cut fromseparate wafers mirror 80 maybe formed in a different way frommirrors mirror 36 needs to be partially reflective to split the returningbeam 70 into two components, themirrors base element 22 is processed separately from thelens element 12, it is convenient to use a different material to makemirror 80 fully reflective. However, if a more complex process is used to permit forming both partially reflective mirror surfaces and fully reflective mirror surfaces during the process sequence, then thelens element 12 andbase element 22 can be cut from a single glass wafer. - Another consideration is the desirability of using essentially
identical photodetectors mirrors beam 70 will fall on each of thephotodetectors mirror 28 can be made in a similar way to mirrors 36 and 38 to be partially reflective, or can be made to be essentially fully reflective. It will also be appreciated that ifmirror 38 is made to be almost fully reflective,mirror 36 can be made to be about 50 percent reflective to have the same light intensity impinging on thephotodetectors laser light beam 82. - According to the preferred process, and with reference to FIGS. 1 and 3,
multiple lens elements 12 are made from a glass wafer, such as thewafer 10, as follows. A first photoresist pattern is formed with openings that define theslots 14 for each of thelens elements 12. Then, a conventional fluoride-based plasma etch step is performed for a time duration that etches openings corresponding to theslots 14 to a depth almost exactly halfway through thewafer 10. Then, a conformal titanium nitride deposition step is performed to coat the walls within the openings with a thin film of titanium nitride, one surface of which later definesmirror 28. The thickness of the titanium nitride deposition is preferably controlled to make themirror 28 more than 90 percent reflective. The photoresist is then stripped and a second photoresist pattern is formed that has openings that define the angled surfaces at the opposite ends of eachlens element 12 where themirrors wafer 10, the openings having walls that include the surfaces on which themirrors mirrors finished lens elements 12. The second photoresist pattern is then stripped off thewafer 10. The thickness of the second titanium nitride deposition is preferably controlled so that themirrors - The process continues with formation of a third photoresist pattern on the
wafer 10 with openings for defining thefront lens 30 of eachelement 12. A plasma etch cuts down into thewafer 10 from thefront surface 26 to a depth that is almost precisely halfway through the thickness of the wafer, which is achieved by controlling the etch duration. When thelens elements 12 are later separated from thewafer 10, thefront lens 30 of eachelement 12 will be provided by this patterning and etching sequence. - Next, the
wafer 10 is turned upside down and a fourth photoresist pattern is formed on the back side of thewafer 10 to define the surfaces that will become the back lens 32 of eachlens element 12. Then, a plasma etch is performed to etch openings in thewafer 10 through corresponding openings in the photoresist pattern to define surfaces that include the surfaces of each back lens 32 of eachlens element 12. The fourth photoresist pattern is then stripped away. As seen in FIG. 3, the result of the etching is that back lens 32 is defined by a surface cut straight down from theback surface 34 halfway through thelens element 12. - A fifth photoresist pattern is formed to define the outlines of the
lens elements 12, as shown in FIG. 1, with their connectingrods 16. This photoresist pattern can be formed on the front side of thewafer 10, or a mirror-image pattern can be formed on the back side. A plasma etch then is performed to cut through thewafer 10 to provide the structures shown in FIG. 1.Individual lens elements 12 are then provided by cutting therods 16 as previously described. - A similar but less complicated sequence of steps can be used to form the
base elements 22 within thewafer 20 of FIG. 2. Since it is desirable formirror 80 to be fully or almost fully reflective, a relatively thick titanium nitride deposition can be used. Alternatively, an aluminum deposition can be performed. In either case, the deposition step proceeds after appropriate windows are etched through a photoresist pattern. If aluminum is used for themirrors 80 of eachbase element 22, a nearly 100 percent reflective surface can be achieved. To keep themirrors 80 from oxidizing and adversely affecting their reflectivity, a thin glass layer is deposited on the aluminum immediately after the metal deposition step. - Although preferred embodiments of the invention have been described, it will be appreciated that various changes can be made without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (20)
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/025,601 US7006426B2 (en) | 2001-12-18 | 2001-12-18 | Integrated optical unit for use with miniature optical discs |
EP02258372A EP1321931B1 (en) | 2001-12-18 | 2002-12-04 | Integrated optical unit for use with minature optical discs |
DE60207184T DE60207184D1 (en) | 2001-12-18 | 2002-12-04 | Integrated optical unit for use with a miniaturized optical disk |
JP2002366524A JP2003203380A (en) | 2001-12-18 | 2002-12-18 | Integrated optical unit for use with miniature optical disc |
US11/248,784 US7323114B2 (en) | 2001-12-18 | 2005-10-12 | Method of making optical elements for an optical disc system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/025,601 US7006426B2 (en) | 2001-12-18 | 2001-12-18 | Integrated optical unit for use with miniature optical discs |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/248,784 Division US7323114B2 (en) | 2001-12-18 | 2005-10-12 | Method of making optical elements for an optical disc system |
Publications (2)
Publication Number | Publication Date |
---|---|
US20030112488A1 true US20030112488A1 (en) | 2003-06-19 |
US7006426B2 US7006426B2 (en) | 2006-02-28 |
Family
ID=21826997
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/025,601 Expired - Lifetime US7006426B2 (en) | 2001-12-18 | 2001-12-18 | Integrated optical unit for use with miniature optical discs |
US11/248,784 Expired - Lifetime US7323114B2 (en) | 2001-12-18 | 2005-10-12 | Method of making optical elements for an optical disc system |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/248,784 Expired - Lifetime US7323114B2 (en) | 2001-12-18 | 2005-10-12 | Method of making optical elements for an optical disc system |
Country Status (4)
Country | Link |
---|---|
US (2) | US7006426B2 (en) |
EP (1) | EP1321931B1 (en) |
JP (1) | JP2003203380A (en) |
DE (1) | DE60207184D1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060133227A1 (en) * | 2004-12-03 | 2006-06-22 | Stmicroelectronics S.A. | Digital disk read/write device |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7701652B2 (en) * | 2002-09-20 | 2010-04-20 | Mems Optical, Inc. | Optical element/device mounting process and apparatus |
JP4401691B2 (en) * | 2003-06-13 | 2010-01-20 | 株式会社オクテック | Method for manufacturing electron beam transmission window of electron beam irradiation tube |
EP2937897A3 (en) | 2003-09-15 | 2016-03-23 | Nuvotronics LLC | Device package and methods for the fabrication and testing thereof |
NL1036695A1 (en) | 2008-05-15 | 2009-11-17 | Asml Netherlands Bv | Lithographic apparatus. |
TWI528064B (en) * | 2012-10-29 | 2016-04-01 | 鴻海精密工業股份有限公司 | Lens and optical module using the same |
US10319654B1 (en) | 2017-12-01 | 2019-06-11 | Cubic Corporation | Integrated chip scale packages |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5583704A (en) * | 1991-10-31 | 1996-12-10 | Asahi Kogaku Kogyo Kabushiki Kaisha | Surface reflecting mirror having a surface reflecting multilayer film |
US5684780A (en) * | 1995-04-18 | 1997-11-04 | Sony Corporation | Optical pickup device having optical element exhibiting polarized light selectivity loaded thereon and optical apparatus having the optical pickup device loaded thereon |
US5689108A (en) * | 1995-05-27 | 1997-11-18 | Victor Company Of Japan, Ltd. | Integrated optical pick-up |
US5783818A (en) * | 1995-05-08 | 1998-07-21 | Matsushita Electric Industrial Co., Ltd. | Integrated type optical pickup having packaging with gas-tight seal |
US5790504A (en) * | 1995-06-02 | 1998-08-04 | Matsushita Electric Industrial Co., Ltd. | Integrated optical head with an emitting light splitting polarizing prism and a detecting light splitting polarizing element |
US6055088A (en) * | 1996-08-22 | 2000-04-25 | Saint-Gobain Vitrage | Glazing with variable optical and/or energetic properties |
US6235141B1 (en) * | 1996-09-27 | 2001-05-22 | Digital Optics Corporation | Method of mass producing and packaging integrated optical subsystems |
US6416194B1 (en) * | 1999-02-11 | 2002-07-09 | Turkiye Sise Ve Cam Fabrikalari A.S. | Thermostable back-surface mirrors |
US6496465B1 (en) * | 1998-06-09 | 2002-12-17 | Barry G. Broome | Monolithic CD/DVD read/write head |
US6529454B1 (en) * | 1998-07-09 | 2003-03-04 | Sony Corporation | Integrated optical component, optical pickup, and optical disc device |
US6542447B1 (en) * | 1999-10-29 | 2003-04-01 | Olympus Optical Co., Ltd. | Magneto-optical pickup |
US6717893B1 (en) * | 2000-10-04 | 2004-04-06 | Dphi Acquisitions, Inc. | Laser thermal management system |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2522861B1 (en) | 1982-03-02 | 1988-01-08 | Thomson Csf | OPTICAL WRITE-READING HEAD OF AN OPTICAL DISC AND OPTICAL DEVICE ASSOCIATED WITH SUCH A HEAD |
JPH05182227A (en) | 1991-12-27 | 1993-07-23 | Matsushita Electric Ind Co Ltd | Optical pickup |
KR950004797B1 (en) | 1991-12-31 | 1995-05-10 | 삼성전자주식회사 | Optical pick up apparatus for cdp |
US6128126A (en) | 1993-04-15 | 2000-10-03 | Balzers Aktiengesellschaft | High-reflection silver mirror |
US5912872A (en) | 1996-09-27 | 1999-06-15 | Digital Optics Corporation | Integrated optical apparatus providing separated beams on a detector and associated methods |
KR100329208B1 (en) * | 1998-06-18 | 2002-03-21 | 니시무로 타이죠 | Functional device and a method for manufacturing thereof and an optical disc apparatus using the functional device |
US6292302B1 (en) | 1998-11-03 | 2001-09-18 | Cardinal Glass Industries, Inc. | Heat-treatable dichroic mirrors |
EP1254453A2 (en) | 1999-12-07 | 2002-11-06 | Dataplay, INC. | Low profile optical head |
US7194016B2 (en) * | 2002-03-22 | 2007-03-20 | The Research Foundation Of The University Of Central Florida | Laser-to-fiber coupling |
-
2001
- 2001-12-18 US US10/025,601 patent/US7006426B2/en not_active Expired - Lifetime
-
2002
- 2002-12-04 DE DE60207184T patent/DE60207184D1/en not_active Expired - Lifetime
- 2002-12-04 EP EP02258372A patent/EP1321931B1/en not_active Expired - Lifetime
- 2002-12-18 JP JP2002366524A patent/JP2003203380A/en active Pending
-
2005
- 2005-10-12 US US11/248,784 patent/US7323114B2/en not_active Expired - Lifetime
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5583704A (en) * | 1991-10-31 | 1996-12-10 | Asahi Kogaku Kogyo Kabushiki Kaisha | Surface reflecting mirror having a surface reflecting multilayer film |
US5684780A (en) * | 1995-04-18 | 1997-11-04 | Sony Corporation | Optical pickup device having optical element exhibiting polarized light selectivity loaded thereon and optical apparatus having the optical pickup device loaded thereon |
US5783818A (en) * | 1995-05-08 | 1998-07-21 | Matsushita Electric Industrial Co., Ltd. | Integrated type optical pickup having packaging with gas-tight seal |
US5689108A (en) * | 1995-05-27 | 1997-11-18 | Victor Company Of Japan, Ltd. | Integrated optical pick-up |
US5790504A (en) * | 1995-06-02 | 1998-08-04 | Matsushita Electric Industrial Co., Ltd. | Integrated optical head with an emitting light splitting polarizing prism and a detecting light splitting polarizing element |
US6055088A (en) * | 1996-08-22 | 2000-04-25 | Saint-Gobain Vitrage | Glazing with variable optical and/or energetic properties |
US6235141B1 (en) * | 1996-09-27 | 2001-05-22 | Digital Optics Corporation | Method of mass producing and packaging integrated optical subsystems |
US6496465B1 (en) * | 1998-06-09 | 2002-12-17 | Barry G. Broome | Monolithic CD/DVD read/write head |
US6529454B1 (en) * | 1998-07-09 | 2003-03-04 | Sony Corporation | Integrated optical component, optical pickup, and optical disc device |
US6416194B1 (en) * | 1999-02-11 | 2002-07-09 | Turkiye Sise Ve Cam Fabrikalari A.S. | Thermostable back-surface mirrors |
US6542447B1 (en) * | 1999-10-29 | 2003-04-01 | Olympus Optical Co., Ltd. | Magneto-optical pickup |
US6717893B1 (en) * | 2000-10-04 | 2004-04-06 | Dphi Acquisitions, Inc. | Laser thermal management system |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060133227A1 (en) * | 2004-12-03 | 2006-06-22 | Stmicroelectronics S.A. | Digital disk read/write device |
US7483346B2 (en) | 2004-12-03 | 2009-01-27 | Stmicroelectronics S.A. | Digital disk read/write device |
Also Published As
Publication number | Publication date |
---|---|
EP1321931A2 (en) | 2003-06-25 |
US7323114B2 (en) | 2008-01-29 |
DE60207184D1 (en) | 2005-12-15 |
US7006426B2 (en) | 2006-02-28 |
JP2003203380A (en) | 2003-07-18 |
EP1321931B1 (en) | 2005-11-09 |
US20060144813A1 (en) | 2006-07-06 |
EP1321931A3 (en) | 2003-10-15 |
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